add TDigest function to the client

Author: AvitalFineRedis

client.go

@@ -443,6 +443,76 @@ func (client *Client) CfInfo(key string) (map[string]int64, error) {
 	return ParseInfoReply(redis.Values(conn.Do("CF.INFO", key)))
 }
 
+// Allocate the memory and initialize the t-digest
+func (client *Client) TdCreate(key string, compression int64) (string, error){
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.CREATE", key, compression))
+}
+
+// Reset the sketch to zero - empty out the sketch and re-initialize it
+func (client *Client) TdReset(key string) (string, error){
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.RESET", key))
+}
+
+// Adds one or more samples to a sketch
+func (client *Client) TdAdd(key string, samples map[string]float64) ([]string, error) )  {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	args := redis.Args{key}
+	for k, v := range samples {
+		args = args.Add(k, v)
+	}
+	reply, err := conn.Do("TDIGEST.ADD", args...)
+	return redis.Strings(reply, err)
+}
+
+// Merges all of the values from 'from' to 'this' sketch
+func (client *Client) TdMerge(toKey string, fromKey string) (string, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.MERGE", toKey, fromKey))
+}
+
+// Get minimum value from the sketch. Will return DBL_MAX if the sketch is empty
+func (client *Client) TdMin(key string) (float64, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.MIN", key))
+}
+
+// Get maximum value from the sketch. Will return DBL_MIN if the sketch is empty
+func (client *Client) TdMax(key string) (float64, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.MAX", key))
+}
+
+// Returns an estimate of the cutoff such that a specified fraction of the data added 
+// to this TDigest would be less than or equal to the cutoff
+func (client *Client) TdQuantile(key string, quantile float64) (float64, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.QUANTILE", key, quantile))
+}
+
+// Returns the fraction of all points added which are <= value
+func (client *Client) TdCdf(key string, value float64) (float64, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return redis.String(conn.Do("TDIGEST.CDF", key, value))
+}
+
+// Returns compression, capacity, total merged and unmerged nodes, the total 
+// compressions made up to date on that key, and merged and unmerged weight.
+func (client *Client) TdInfo(key string) (map[string]int64, error) {
+	conn := client.Pool.Get()
+	defer conn.Close()
+	return ParseInfoReply(redis.Values(conn.Do("TDIGEST.INFO", key)))
+}
+
 func ParseInfoReply(values []interface{}, err error) (map[string]int64, error) {
 	if err != nil {
 		return nil, err